Context watermark for digital contents

Abstract

A method for context watermarking includes the steps of performing a Hash function “D” of the digital content ( 502 ). A Hash function “C” of the context information is also calculated ( 504 ). The Hash “D” is then appended to the context information ( 506 ) while the Hash “C” is appended to the digital content ( 508 ). The augmented content and context information are then packaged together ( 510 ) with the Hash values “D” and “C” helping to bind the content and context together. Instead of using Hash function other more sophisticated signatures can be used like those produced using Discrete Wavelet Transforms (DWT) or fractal-based transforms. An electronic device such as a radio communication device ( 700 ) capable of performing context watermarking is also described.

1 . A method for providing context information watermarking for digital content, comprising the steps of: 
 (a) calculating a transform function value “D” of the digital content;    (b) calculating a transform function value “C” of the context information;    (c) appending the transform function value “D” to the context information; and    (d) appending the transform function value “C” to the digital content.    
   
   
       2 . A method as defined in  claim 1 , wherein the transform function used in steps (a)-(d) are Hash functions.  
   
   
       3 . A method as defined in  claim 1 , wherein the transform function used in steps (a)-(d) is a Discrete Wavelet Transform (DWT).  
   
   
       4 . A method as defined in  claim 1 , wherein the transform function used in steps (a)-(d) is a fractal-based transform  
   
   
       5 . A method as defined in  claim 2 , further step of: 
 (e) packaging the results of steps (c) and (d) so that the Hash values “D” and “C” bind the content and context information together.    
   
   
       6 . A method as defined in  claim 3 , further comprising the step of: 
 (f) encrypting the digital content.    
   
   
       7 . A method as defined in  claim 3 , further comprising the step of: 
 (f) encrypting the context information.    
   
   
       8 . A method as defined in  claim 6 , wherein the encrypting of step (f) is performed using a secret encryption key that is packaged with the digital content or the context information.  
   
   
       9 . A method as defined in  claim 2 , wherein the period in which the context watermarking is performed is predefined.  
   
   
       10 . A method as defined in  claim 2 , wherein the period in which the context watermarking is performed is adjusted dynamically based on how fast the context information is changing.  
   
   
       11 . A method as defined in  claim 10 , wherein the dynamic adjustment of the context watermarking is performed using a dynamic capture period controller.  
   
   
       12 . An electronic device that can perform context watermarking of digital content, comprising: 
 a content capturing device;    a context capturing device; and    a controller coupled to the content and context capturing devices, the controller calculates a transform function value “D” of the digital content received by the content capturing device and calculates a transform function value “C” of the context information captured by the context capturing device, it also appends the transform function value “D” to the context information and appends the transform function value “C” to the digital content.    
   
   
       13 . An electronic device as defined in  claim 12 , wherein the controller further packages the results so that the transform function values “D” and “C” bind the content and context information together.  
   
   
       14 . An electronic device as defined in  claim 13 , wherein the electronic device comprises a radio communication device.  
   
   
       15 . An electronic device as defined in  claim 13 , wherein the controller also encrypts the context information or digital content.  
   
   
       16 . An electronic device as defined in  claim 13 , further comprising a dynamic capture period control circuit coupled to the controller that adjusts dynamically the context watermarking based on how fast the context information is changing.  
   
   
       17 . An electronic device as defined in  claim 13 , wherein the transform function used comprises a Hash function.  
   
   
       18 . An electronic device as defined in  claim 13 , wherein the transform function used comprises a Discrete Wavelet Transform (DWT).  
   
   
       19 . An electronic device as defined in  claim 13 , wherein the transform function used comprises a fractal-based transform.  
   
   
       20 . A method for providing context watermarking in a radio communication device that captures both digital content and context information, comprising the steps of: 
 (a) calculating a hash function value “D” of the digital content;    (b) calculating a hash function value “C” of the context information;    (c) appending the hash function value “D” to the context information;    (d) appending the hash function value “C” to the digital content; and    (e) packaging the results of steps (c) and (d) so that the Hash values “D” and “C” bind the digital content and context information together.    
   
   
       21 . A method as defined in  claim 20 , further comprising the step of: 
 (f) encrypting the context information.    
   
   
       22 . A method as defined in  claim 21 , wherein the encrypting in step (f) is performed using a secret encryption key that is packaged with the digital content or the context information.